Written & medically reviewed by Dr. Sanjay Anbu, MBBS· Last reviewed
Ondansetron is a strong anti-sickness medicine that blocks the nausea signal. It is widely used for vomiting from infections, chemotherapy, or after surgery.
Typical dose — general reference only, NOT a prescription
Measure
Range
Category
Prescription
Adult dose
4–8 mg every 8–12 hours as needed
Child (paediatric) dose
Weight-based, about 0.15 mg/kg per dose — doctor only
What it is used for
Vomiting from gastroenteritis or infections
Nausea from chemotherapy or after surgery
Severe vomiting in pregnancy (specialist advice)
Common brand names
India: Emeset, Ondem, Vomikind, Osetron
Worldwide: Zofran, Zuplenz
Common side effects
Constipation
Headache
Tiredness
Before taking it — precautions
Caution with heart-rhythm problems
Tell your doctor about other medicines
Not a substitute for rehydration in diarrhoea
When to see a doctor urgently
Palpitations or fainting (heart-rhythm effect)
Severe constipation
Allergic reaction
Doses are a general reference, not a prescription. Doses shown are typical adult/paediatric references and vary with age, weight, kidney/liver function and the exact product. Paediatric doses are usually weight-based and must be set by a doctor. MedDroid cannot prescribe — always confirm ondansetron and your dose with a doctor or pharmacist and the leaflet inside the pack.
Frequently asked questions
Is ondansetron better than domperidone?
Ondansetron is often more effective for significant vomiting; domperidone also helps bloating. The choice depends on the cause and your heart health.
Can I use ondansetron for a stomach bug?
A doctor may use it to control vomiting so you can keep fluids down, but rehydration with ORS remains the key treatment.
Reviewed by Dr. Sanjay Anbu, MBBS. MedDroid is an AI medical assistant and can make mistakes. It provides general health information, not a diagnosis or medical advice — always consult a qualified clinician. In an emergency, contact your local emergency number immediately.